The hypertension guidelines suggest a 3-5 minutes rest period prior to blood pressure (BP) measurement. Yet, it could be difficult to execute. The researchers carried out a randomized trial to decide the impact of resting for less than 5 minutes on BP. There were 113 participants (mean age 55 years, 36% male, 75% Black) in a cross-over design. Each participant had 4 sets of triplicate BP measurements with the order of rest for the first 3 sets (0 minutes, 2 minutes, and 5 minutes1) randomized. The researchers calculated the difference between 5 minutes1 and 5 minutes2 (5 minutes1−5 minutes2), a measure of intrinsic BP variability, by keeping the fourth set fixed as a second 5-minute rest period (5 minutes2). They also tested if 5 minutes1−0 minutes or 5 minutes1−2 minutes was within a prespecified noninferiority margin of ±2 mm Hg compared with 5 minutes1−5 minutes2 to judge if there was no difference between BPs obtained after resting 0 minutes or 2 minutes against 5 minutes1.
The mean BP was similar across 5 minutes1 (128/75), 5 minutes2 (127/76), 2 minutes (127/74), and 0 minutes (127/74). The absolute systolic BP (SBP) difference of differences did not cross our noninferiority margin for 0 minutes rest (0.2 [95% CI, 0.8–1.2]) when compared to the average absolute 5 minutes1−5 minutes2 difference (5.3/3.0 mm Hg). However, it did cross the margin for 2 minutes rest (−1.7 [−2.8 to −0.6]). The absolute difference of differences for both 0 and 2 minutes did not cross the ±2 mm Hg margin in the participants whose SBP was less than 140 mm Hg. On the other hand, participants, with SBP greater than or equal to 140 mm Hg, exhibited differences that surpassed the threshold.
The researchers concluded that, for most individuals, the shorter rest period might be feasible compared to the five minutes interval. The execution of the said procedure could considerably improve the hypertension screening programs efficiency.